Electrodeposition of antimony



Patented July 6, 1954 ELECTRODEPOSITION F ANTIMONY John D. Little, Bay Village, Ohio, assignor to The Harshaw Chemical Company, Cleveland, Ohio, a corporation of Ohio No Drawing. Application December 4, 1952, SerialNo. 324,140

9 Claims. 1

This invention relates to electrodeposition of antimony and more especially to electrodeposition of adherent and lustrous deposits of antimony.

It'is an object of the invention to deposit on cathode surfaces adherent deposits of high quality and having sufficient lustre to eliminate or greatly reduce buffing necessary to achieve full brightness. Other and more specific objects of the invention will become apparent as the de scription proceeds.

No completely satisfactory method of causing an antimony electrodeposit to adhere to steel directly is known, so far as I am aware. However lead, tin, and silver adhere well to steel and in accordance with the present invention antimony can be made to adhere well to lead, tin or silver or alloys of two or morethereof and exhibit semibrightness or full brightness by the inclusion in a plating solution of aqueous, acid antimony type, from which deposits on lead, tin, or silver (or their alloys as indicated) are to be taken, of cooperating addition agents. Lustrous and usefully adherent deposits directly on roughened steel (e. g., sand blasted or etched) can also be produced from solutions according to the present invention. a

The fundamental plating bath should'be a aqueous, acid solution of an antimony compound,

suitable antimony trifiuoride, which should also contain means for adjusting the pH of the solution and means for holding the antimony in solution, that is, means for preventing precipitation of antimony up to a concentration of at least about 0.7 mol and preferably up to 1.5 mols of SbFs per liter. The pH may be adjusted by means of ammonium ion or less desirably by sodium or potassium ion. An amine such as triethanolamine may be used for adjusting pH. Precipitation of antimony fluoride may be pre vented by the use of an alpha-hydroxy carboxylic acid such as tartaric, citric, gluconic, glycolic, or lactic acid or by the ammonium, sodium, or

potassium or amine salt thereof or an excess of fluoride ion in a fluoride solution. In case the salt is used, it can be also, at least in part, the

means for adjusting the pH of the solution. For

example, antimony trifluoride, ammonium glycolate, and water make a fundamental bath in which addition agents according to the invention may be used. Antimony chloride may be substituted in part for antimony fluoride in the fluoride bath, for example up to 40% by weight of the antimony content. The pH should befrom 3.5 to 5.0.

For solutions containing antimony fluoride, the

quantity of alpha-hydroxy carboxylic acid, if used, may be within the range of A; to 2 hydroxy equivalent weights of the acid per atomic weight of antimony, the preferred concentration being about 1 alpha hydroxy equivalent weight of acid per atomic weight of antimony. (By alpha hydroxy equivalent weight is meant the molecular Weight of the alpha hydroxy acid divided by the number of its alpha hydroxy groups.)

Sulfate ion is desirable as a means for insuring against immersion deposition and, when used should preferably be present in concentration from 50 to mol per cent of the alpha hydroxy acid. Sulfate ion is not absolutely essential but is highly desirable for the purpose indicated.

In making up the solutions, the adjustment of the pI-i may be accomplished or partly so by the choice of compounds. Thus, for example, by using SbzOs and NHaFI-IF, SbFz is produced in situ in the bath or in the tank used for manufacture of concentrate and ammonia is left over for reaction with alpha hydroxy or other acid and thus raises the pI-I. Additional alkaline material may or may not be needed to secure the desired pI-I. As a practical matter, it is very desirable .to form a bath or a concentrate which requires little if any addition of ammonia to the platers tank. Also, it is cheaper to make use of antimony oxide and an ammonium fluoride instead of using antimony trifluoride as such in making up baths or concentrates. As shown by Examples 13 and 14, Table III, it is feasible to operate without further adjustment of pH after making up the solutionsthere indicated.

Preferred solutions consist of SbzOs, NHILFHF and glycolic acid in proportions to yield SbFa and ammonium glycolate, each from 0.5 to 2 and NHdOH to yield a pH from 2.5 to 5.0.

Addition agents used in the above described solutions are of two classes, the first comprising benzene sulfonamides such as those listed in Table I which should be present to the extent of from 0.5'to 6 grams per liter and the second comprising a-ryl guanidines such as those listed in Table II, which should be present in concentration from 01005 to 0.07 gram per liter.

Table I Benzene sulfonamide, CeHaSOzNHz Toluene sulfonamide, CH3CGH4SO2NH2 Di-benzene sulfonamide, CsI-I5SO2NHSO2CcI-I5 Bi-di-benzene sulfonamide,

Di-benzene sulfonamide ether,

CsH5SQ2NHSO2CsH4OCsI-I4S02NHSOaCeI-Is 3 Table II Diphenyl guanidine, (CsH5NH)2C=NH Triphenyl guanidine, (sHsNI-I) 2S=NC6H Specific examples of batch formulations for plating solutions according to the invention employing representative examples of these addition agents are shown in Table III. All the examples shown in said table yield deposits which are firmly adherent to lead, tin and silver and fairly adherent to roughened steel and exhibit improved lustre resulting from the presence of the cooperating addition agents.

Table III Example Preferred Range 1. 511013, .87 molll .5l.5 mols/l.

NaF, 2.61 mols/l 1.5-4.5 mols/l. Tartaric acid, 0.8 mol/l .25-1.5 mols/l. NsOH to pH, 3.0 2.7-3.5. Dibenzene sulionamide, 2 g /l. 1-4 gJl. Diphenyl guauidinc, .02 g./l .01-.05 g./1

, 2. SbOli. 1.25 mols/l 5-1.o mols/l NILFJIF, 1.875 mols/l 7-2.5 mols/l Ammonium citrate, .31 moi/l .1-.6 mol/l NHiOH to pI-I, 4.0 2.5-5. Dibenzene sulfonamide. 3.0 g./l 1-5 g./l. Diphenyl guanidine, .02 g./1 .01-.05 g./l

3. SbFa. 1.25 mol 5-1.5 mols/l (NHDzSOi. 1.25 mols/l... 25-1 5 mols/l Glvcclic Acid, 0.75 moi/1 .25-l.5 mols/l. NH4OH to pH 4.0 2.5-4.5. Dibcnzene sulfonamide, 1.0 g./l 0.5-6.0 g./l. Diphenyl guanidine, 0.01 g./l 005-007 g /l 4 zOa, 0.62 moi/l 25-.75 ncl/l H2804, 1.25 mols/l... 50-150 mols/l Kl HF, 1.87 mols/L. .75-2.25 mols /l Gliiconic Acid, 75 moi/l 2.5-1.50 mols/l. KOH to pH 4.5 2.5-5.0. Dibenzene sulfonamide, 1.0 g./l. 0 -6.0 g./l Diphenyl guanidine, 0.01 g./l. 0 005-007 g /1 5. SbzOs, 0.7 mol/l 31.0 mol HF, 4.2 mols/l 6-2.0 mols/l Tartaric acid, .35 mol/l. 2.5-1.5 mols/l Triethanolamine to pI-I 4.0. 2.5-5.0, Dibenzcnc sulfonamide, 2 g./l 1-5 g.[l. Diphenyl guanidine, .02 g./l .01-.05 g./l.

6. 313203, 0.62 moi/l .3- .0 mol/l.

NHJYHF, 1.85 mols/L. 1.0-3.0 mols/l. Glycolic acid, 1.23 mole/1. 0.6-2.0 mols/l. NH4OH to pH 4.0 2.5-5. Dibenzcne sulfonamide, 0.5 g./l .5-2 g./l. Bi-dibcnzene sulfonamidc, 2.0 g./l. .5-2 g./l. Diphenyl guanidine, 0.04 g./l 01-.05 g./l

7. Sbz03. 0.62 mol/l 3-1 0 mol/l. NHiEHF, 1.85 mols/L. 1-3 mols/l Glycolic acid, 1.23 mols/L 6-2 mols/l (NHmSOi. 50 to 150 mol percent of the glycolic acid. NH4OI'I to pH 4.0 2 5-4.0. Dibenzene sulionamidc. 3 g./l l-6 g., 1. 'lriohcnyl guanidinc. .03 g./l 01-.1 g./l.

8. bzOn, 0.62 mo .3-1.0 mol/l.

Nl-liFlIF, 1.85 mols/l 1.0-3.0 mols/l Glycolic acid. 1.23 mols l .62.0 mols/l. Nrrmsor 50 to 150 mol percent of the glycolic acid. NILOI-I to pH 4.0 2.5-5. Dibenzene sultonamidc ether, 2.0 g./l .5-4 g./l. Diphenyl guanidinc .0 [1 01-01 g./]

9. SbzOa. 0.62 moi/1.." 6-1.0 moi/l NH RHF, 1.85 mol 1.0-3.0 mole/1. Glycolic acid, 1.23 mols -2.0 mols/l. (NllmsOi. 50 to 150 mol percent of the glycolic acid. NH4OH to p11 4.0 l 2.5-5.0. 011g0110 sulionagiidc, 0i [l 26%? gag/1il i en l uani inc, g 10. p v g 01 l g .25-.75 mol/l.

.5-1.50 mols/l. .5-1.50 mols/l. .5-1.50 mols/l. .5-1.50 mols/l. NH4OH to pH 4.0 2.5-4.5. Dibenzene sulfonamide, 2.0 0.5-6.0 g/l. Diphenyl guanidine, 0.02 g/l. 0.005-0.07 g/l.

11. Sb1 1.4 mols/l 8-1.5 mols/l.

11111, 5.4 mols/l. 4 06.0 mols/l. NHiOH to UK 3 5 3.0-4.7. Dibcnzcnc sulfonarnid 2. g 2.0-6.0 g/l Triplienyl guanidine, .02 g/L. .01-.04 g/l.

12. .81.5 mols/l.

. 4.0-6.0 mols/l NH4OH to pH 3.5 3.0-4.7. Benzene sulfonamide, 2.0 g 1-2.5 g/l.

. Diohenyl guanidine, .01 g/L. .005-.03 g/l.

13. SbFg, 1.23 mols /l 0.8-1.5 mols/l. Ammonium glycolate, 1.23 mols/ 0.6-2.0 mols/l. Dibcnzene sulfonamide, 2.0 g/l 0.5-6.0 g/l. Diphenyl guanid'me, 0.02 g/l 0.005-0.07 g/l.

Table III-Continued Example Preferred Range 14. Sbl3 1.23 mols/l 0.8-1.5 mols/l Ammonium glycolate, 1. m 0.6-2.0 mols/l Ammonium sulfate, 1.23 mols/l 0.6-1.8 mols/l Dibenzene sulfonamide, 2.0 g/l. 0.5-0 g/l. Diphenyl guanidine, 0.02 g/l. 0.005-0.07 g/l 15. SbzOz, .172 mol/l l5.20 moi/l Citric acid, .96 mo1/l 5-1.0 moi/l Potassium citrate, .445 m 4-.6 mol/l KOH to pH 4.2 3.0-4.5. Dibenzene sulionamide, 2 g/l 1-5 g/l. Dipnenyl guanidine, .02 g/l 01-.03 g/l. 16. S5013, .153 moi/1 13-.18 mol/l Oxalic acid, .119 mol/l 10-.20 mol/l Ammonium oxalate, .8 mol/l 70-1.0 mol/l NHrOH to pH 4.0 3.0-4.5. Dibenzene sulfonamide, 2 g/l. l-5 g/l. Diphenyl guanidine, .02 g/l 01-.03 g/l. 17. Tartar emetic, .15 mol/l 10-.30 mol/l Ammonium citrate, .206 mol/l .2-.5 moi/1. pH 4.0 3-4.5 mols/l Dibcnzene sulfonamide, 1 g/l 0.5-2.0 g/l. Diphenyl guanldine, .02 g/l .01-.03 g/l.

Temperature is not sharply critical but may be suitably in the range from to F.

Cathode current density is, likewise, not sharply critical but preferably is in the range from 10 to 200 amperes per square foot.

Having thus described the invention, What is claimed is:

1. A process for electrodeposition of an adherent, lustrous coating of antimony on lead comprising electrolyzing between an antimony anode and a lead cathode an aqueous, acid solution aifording a source of antimony ions and containing cooperating adherence promoting and brightening addition agents one thereof being of the class consisting of benzene sulfonamide, dibenzene sulfonamide, bi-di-benzene sulfonamide, di-benzene sulfonamide ether, and toluene sulfonamide and being present in solution in concentration from 0.5 to 6 grams per liter, and the other thereof being of the class consisting of diphenyl guanidine and triphenyl guanidine and being present in concentration from 0.005 to 0.07 gram per liter.

2. A process for electrodeposition of an adherent, lustrous coating of antimony on lead comprising electrolyzing between an antimony anode and a lead cathode an aqueous, acid solution of antimony tri-fluoride, the pH of said solution being from 2.5 to 5.0, and said solution containing cooperating adherence promoting and brightening addition agents one thereof being of the class consisting of benzene sulfonamide, di-benzene sulfonamide, bi-di-benzene sulfonamide, di-benzene sulfonamide ether, and toluene sulfonamide and being present in solution in concentration from 0.5 to 6 grams per liter, and the other thereof being of the class consisting of diphenyl guanidine and triphenyl guanidine and being present in concentration from 0.005 to 0.07 gram per liter.

3. A process for electrodeposition of an adherent, lustrous coating of antimony on surfaces of the class consisting of lead, tin, silver, alloys of a plurality thereof and rough steel, comprising electrolyzing between an anode and a cathode of said class an aqueous, acid solution containing an antimony compound affording a source of antimony ions and means for adjusting the pH of said solution to form 2.5 to 5.0, said solution also containing cooperating adherence promoting and brightening addition agents one thereof being of the class consisting of benzene sulfonamide, (ii-benzene sulfonamide, bi-di-benzene sulfonamide, di-benzene sulfonamide ether, and toluene sulfonamide and being present in solution in concentration from 0.5 to 6 grams per liter, and the other thereof being of the class consisting of diphenyl guanidine and triphenyl guanidine and being present in concentration from 0.005 to 0.07 gram per liter.

4. A process for electrodeposition of an adherent, lustrous coating of antimony on surfaces of the class consisting of lead, tin, silver, alloys of a plurality thereof and rough steel, comprising electrolyzing between an antimony anode and a cathode of said class, an aqueous, acid solution containing an antimony compound affording a source of antimony ions, means for holding said antimony compound in solution to a concentration in the range from 0.7 to 1.5 mols of said antimony compound per liter of solution and means for adjusting the pH of said solution to from 2.5 to 5.0, said solution also containing cooperating adherence promoting and brightening addition agents one thereof being of the class consisting of benzene sulfonamide, di-benzene sulfonamide, bi-di-benzene sulfonamide, di-benzene sulfonamide ether, and toluene sulfonamide and being present in solution in concentration from 0.5 to 6 grams per liter, and the other thereof being of the class consisting of diphenyl guanidine and triphenyl guanidine and being present in concentration from 0.005 to 0.07 gram per liter.

5. A process for electrodeposition of an adherent, lustrous coating of antimony on a metal base comprising electrolyzing between an antimony anode and a cathode of the class consisting of lead, tin,v silver, alloys of a plurality thereof and rough steel, an aqueous, acid solution containing antimony trifluoride, means for holding said antimony trifiuoride in solution up to a concentration in the range from 0.7 to 1.5 mols per liter and comprising an alpha-hydroxy car boxylic acid in concentration from /8 to 2 hydroxy equivalents per atomic weight of antimony, said solution also containing sulfate ion and cooperating adherence promoting and brightening addition agents one thereof being of the class consisting of benzene sulfonamide, di-benzene sulfonamide, bi-di-benzene sulfonamide, di-ben- 'zene sulfonamide ether, and toluene sulfonamide and being present in solution in concentration from 0.5 to 6 grams per liter, and the other thereof being of' the class consisting of diphenyl guanidine and triphenyl guanidine and being present in solution in concentration from 0.005

, to 0.07 gram per liter.

' 6. A process for electrodeposition of an adherent, lustrous coating of antimony on lead com- 6 other thereof being of the class consisting of diphenyl guanidine and triphenyl guanidine and being present in solution in concentration from 0.005 to 0.07 gram per liter.

7. A process for electrodeposition of an adherent, lustrous coating of antimony on lead comprising electrolyzing between an antimony anode and a lead cathode an aqueous, acid solution affording a source of antimony ions and containing from 0.7 to 1.5 mols per liter of antimony trifluoride, a radical of the class consisting of glycolate, tartrate, citrate, gluconate, and lactate in concentration from A; to 2 hydroxy equivalents per atomic weight of antimony, said solution also containing sulfate ion and means for adjusting the pH to from 2.5 to 5.0 and 00-- operating adherence promoting and brightening addition agents one thereof being of the class consisting of benzene sulfonamide, di-benzene sulfonamide, bi-di-benzene sulfonamide, diben'rene sulfonamide ether, and toluene sulfonamide and being present in solution in concentration from 0.5 to 6 grams per liter, and the other thereof being of the class consisting of diphenyl guanidine and triphenyl guanidine and being present in concentration from 0.005 to 0.07 gram per liter.

8. An aqueous, acid electroplating solution for electrodeposition of antimony, the same containing: 1

Antimony trifluorlde 0.5 to 2 mols per liter.

Ammonium glycolatc 0.5 to 2 mols per liter.

Sulfate ion to mol percent of the ammonium glycclate.

Dibenzene sulfonamide 0.5 to 6 grams per liter.

Diphenyl guanidine 0.005 to 0.07 gram per liter. Ammonium hydroxide to pH 2.5 to 5.0.

9. A process for electrodeposition of an adherent, lustrous coating of antimony on lead comprising electrolyzing between an antimony anode and a lead cathode an aqueous, acid solution affording a source of antimony ions and containing antimony triiiuoride in concentration in the range from 0.7 to 1.5 mols per liter, means for holding said antimony trifluoride in solution in said concentration and comprising an alphahydroxy carboxylic acid present in concentration from A; to 2 hydroxy equivalents per atomic weight of antimony, said solution also contain ing sulfate ion to the extent of from 50 to 150 mol per cent ofsaid alpha hydroxy carboxylic acid and cooperating adherence promoting and brightening addition agents one thereof being of the class consisting of benzene sulfonamide, dibenzene sulfonamide, bi-di-benzene sulfonamide, di-benzene sulfonamide ether, and toiuene sulfonamide and being present in solution in con centration from 0.5 to 6 grams per liter, and the other thereof being of the class consisting of diphenyl guanidine and. triphenyl guanidine and being present in solution in concentration from 0.005 to 0.07 gram per liter.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,389,131 Bloom Nov. 20, 1945 2,441,810 Glover et a1 May 18, 1948 

3. A PROCESS FOR ELECTRODEPOSITION OF AN ADHERENT, LUSTROUS COATING OF ANTIMONY ON SURFACES OF THE CLASS CONSISTING OF LEAD, TIN, SILVER, ALLOYS OF A PLURALITY THEREOF AND ROUGH STEEL, COMPRISING ELECTROLYZING BETWEEN AN ANODE AND A CATHODE OF SAID CLASS AN AQUEOUS, ACID SOLUTION CONTAINING AN ANTIMONY COMPOUND AFFORDING A SOURCE OF ANTIMONY IONS AND MEANS FOR ADDJUSTING THE PH OF SAID SOLUTION TO FROM 2.5 TO 5.0, SAID SOLUTION ALSO CONTAINING COOPERATING ADHERENCE PROMOTING AND BRIGHTENING ADDITION AGENTS ONE THEREOF BEING OF THE CLASS CONSISTING OF BENZENE SULFONAMIDE, DI-BENZENE SULFONAMIDE ETHER, AND FONAMIDE, DI-BENZENE SULFONAMIDE ETHER, AND TOLUENE SULFONAMIDE AND BEING PRESENT IN SOLUTION IN CONCENTRATION FROM 0.5 TO 6 GRAMS PER LITER, AND THE OTHER THEREOF BEING OF THE CLASS CONSISTING OF DIPHENYL GUANIDINE AND TRIPHENYL GUANIDINE AND BEING PRESENT IN CONCENTRATION FROM 0.005 TO 0.07 GRAM PER LITER. 